1. Technical Field of the Invention
The invention concerns a process for making photovoltaic modules and further a device to implement said process. Photovoltaic modules are solar energy generators and consist of a laminate containing as its core a system of solar cells such as silicon cells. This core layer allows only slight mechanical stresses and is imbedded in encapsulating materials. Such materials may be composed of one or more glass and/or plastic-foil layers and/or of plastic-foil composites.
2. State of the Art
U.S. Pat. No. 4,421,589 discloses the manufacture of known photovoltaic modules using vacuum lamination. A vacuum laminator is used which is divided by a flexible membrane into vacuum chambers, one chamber receiving a stack resting on a plate and constituted by the solar-cell system and the encapsulating materials and, where called for, separating foils. The plate temperature is kept below the softening point of the encapsulating materials. Next the two chambers are evacuated and the plate temperature is raised to the softening point of said encapsulating materials. Subsequently the upper chamber is ventilated and as a result the flexible membrane is forced against the stack. Thereby a composite is formed, composed of the system of solar cells and the encapsulating materials. The encapsulating materials are hardened by further raising the temperature and thereafter the plate is cooled and the laminate is removed from the vacuum chamber.
This procedure is very time-consuming because only one photovoltaic module at a time may be manufactured in one operational step. Moreover the plate in the vacuum laminator is used both as a heating and a cooling plate, whereby high energy losses are incurred.